Missed abortion is an intrauterine death of an embryo or fetus, which is accompanied by myometrial areactivity and fetal egg retention in the uterine cavity. Initially, there are no signs of the threat of spontaneous miscarriage, but later spotting appears, the size of the uterus lags behind the gestation period. For diagnosis, ultrasound is performed, a blood test for hCG. Treatment depends on the duration of pregnancy. Up to 14 weeks, vacuum aspiration, curettage of the uterine cavity is possible. In the 2nd trimester, oxytocin is injected intravenously or prostaglandins into the amnion cavity.
O02.1 Missed abortion
Missed abortion, or an undeveloped pregnancy, accounts for 45-90% of all cases of spontaneous gestation interruptions. Pathology occurs more often at the beginning of the gestation period, about 20% of cases are observed in the second trimester. The bulk of the patients are re–pregnant women, most of them did not plan conception. In half of pregnant women, emptying of the uterine cavity occurs spontaneously within 14 days, but in the third part, the remains of the embryo are delayed for a longer period, which is an indication for obstetric and gynecological care.
Missed abortion is characterized by the fact that when the development of the embryo stops and its death, the expulsion of the fetal egg does not occur. This is possible with a violation of the neurohumoral regulation of myometrial contractility. The development of pathology is influenced by several factors at the same time, the main causes are:
- Chronic endometritis. It is diagnosed in most women with a missed abortion. Most often, microbial associations are determined from conditionally pathogenic microorganisms, herpes virus, chlamydia, gonococci, trichomonas, cytomegalovirus are detected.
- Tight attachment of the chorion. With structural inferiority of the endometrium caused by endometritis, frequent abortions and high proliferative activity of trophoblast villi, the forming placenta grows deeply into the uterine wall and delays miscarriage.
- Immune factors. Rejection of the deceased embryo does not occur with high immunological compatibility of mother and fetus. In some cases, pronounced immunosuppression is observed under the influence of progesterone-induced blocking protein – a specific protein of pregnant women.
- Contractile hypofunction of the myometrium. Chronic inflammation reduces the number of receptors for endogenous uterotonics. In case of metabolic disorders, there is a deficiency of enzymes and hormonal factors involved in the expulsion of the fetus.
Missed abortion is more often associated with chronic endometritis, other factors act as additional. Viruses or bacteria that persist in the genitals can damage the cells of the embryo. Under the influence of infectious factors, the immune system is activated, the synthesis of inflammatory cytokines increases, the production of growth factors decreases, invasion is disrupted and trophoblast cells are damaged.
With a missed abortion up to 5 weeks, the fetal egg persists and continues to develop, but anembryonia is diagnosed due to autolysis of its contents. If the infection occurred after the laying of internal organs, fetal death may occur at a later date, therefore, a fetus whose size does not correspond to the day of gestation is detected. Rejection does not occur due to a decrease in endometrial reactivity.
A dead embryo can linger inside the uterine cavity for 20 days or more. Its tissues undergo destruction and necrosis, and later are able to mummify or petrify. With the preservation of embryonic remains for more than a month, blood clotting factors are released, coagulopathy develops, which can turn into DIC syndrome.
Missed abortion may develop in the 1st or 2nd trimester, for later periods this definition is not used. In the 3rd trimester, the condition is called antenatal death. In clinical gynecology, a classification is adopted depending on the gestation period in which the complication developed:
- Early. Occurs before 12 weeks of pregnancy.
- Late. The fetus dies in the period from 12 weeks to the 21st week of gestation.
When the embryo dies, subjective sensations are absent for a long time. After 10-14 days, due to hormonal changes, the nonspecific signs of carrying a child decrease. The patient feels the disappearance of morning sickness, breast tenderness, fatigue and drowsiness. Appetite and mood gradually return to normal, but amenorrhea persists.
If the child dies at the end of the 2nd trimester, the pregnant woman ceases to feel his stirring, the size of the abdomen stops increasing, the body weight also does not grow. Pain over the womb, which radiates into the sacrum, groin area or perineum, begins to bother 14-30 days after a failed spontaneous miscarriage. At the same time, spotting bloody discharge from the genital tract may appear.
Sometimes amniotic fluid is absorbed into the mother’s bloodstream, the deceased fetus is dehydrated and mummified. The deposition of calcium salts in the tissues of the child causes petrification. Such changes occur with prolonged fetal retention in the uterine cavity. A mummified and calcified fetus can be asymptomatic in the uterus for years.
With prolonged preservation of the remains of the embryo, concomitant colpitis, endometritis, an infected abortion occurs. In a pregnant woman, signs of intoxication become pronounced, body temperature rises, fetid secretions appear from the genital tract. If you do not start treatment, pathogens are disseminated to the pelvic cavity, pelvioperitonitis, peritonitis and sepsis develop.
With prolonged preservation of the deceased embryo, the blood clotting system is activated. This causes coagulopathy, hemostasis disorders. Therefore, a pregnant woman with a failed spontaneous miscarriage has a high risk of severe uterine bleeding and DIC syndrome.
An examination of a woman with a suspicion of a missed abortion is carried out by an obstetrician-gynecologist of a women’s consultation. In the early period, dynamic monitoring is necessary to confirm the diagnosis. Consultation with an anesthesiologist is carried out only when surgical treatment is prescribed or there is a risk of severe complications. The following methods are used for diagnosis:
- Gynecological examination. The height of the uterine fundus is less than the gestation period, during vaginal examination, the cervix is closed, small spotting may be observed.
- Ultrasound of the uterine cavity. The size of the uterus lags behind the gestation period by 2 weeks or more. In the 1st trimester, anembryonia can be determined – an empty fetal egg. In other cases, there is no fetal heartbeat, and after 12 weeks there are no signs of stirring.
- HCG analysis. The failed interruption is accompanied by a discrepancy in the concentration of the hormone in the blood during gestation. Upon repeated examination, the hCG level decreases rapidly, which confirms the death of the embryo.
- Coagulogram. A missed abortion is an indication for determining blood clotting time, APTT, INR, prothrombin time and fibrinogen in order to anticipate hemostasis disorders and prevent them in time.
After the death of the embryo, the preservation of pregnancy is impossible. Hospitalization to the gynecological department is mandatory to remove fetal remains and monitor the patient. Outpatient rehabilitation and treatment of concomitant chronic endometritis can be carried out. In case of a missed abortion, the following methods of therapy are used:
- Vacuum aspiration. It can be used in pregnant women up to 14 weeks. This is a gentle method of treatment that does not damage the uterine walls. The procedure is performed under general anesthesia.
- Curettage of the uterine cavity. Manipulation is carried out up to 12-14 weeks under anesthesia. Curettage requires expansion of the cervical canal. Special tools are used to remove the mucous membrane, the remains of the fetal egg.
- Introduction of prostaglandins. After 14 weeks, the drugs are injected into the amniotic cavity in the form of a solution or into the vagina in the form of candles. The drug causes the opening of the cervical canal, contractions of the myometrium and rejection of the remains of the fetal egg.
- The use of misoprostol. The drug is effective for up to 24 weeks. The dosage is selected individually, in the first trimester it is 2 times more than in the second. Miscarriage occurs after 2-5 days.
- Oxytocin injections. The hormone causes uterine contractions, but sensitivity to it appears only from the 20th week of gestation. To cause a miscarriage, the drug is administered in a large dose intravenously.
Prognosis and prevention
For a woman with a diagnosed missed abortion, the prognosis depends on the time of the visit to the doctor and the cause of the disease. With chronic endometritis, there is a possibility of a recurrence of this condition, therefore, examination for sexually transmitted infections and their treatment is necessary. After the addition of uterine bleeding, DIC syndrome, the risk of severe consequences or death increases.
To prevent pregnancy complications, it is necessary to plan conception, treat sexual infections and somatic pathologies. To protect against infection, you should avoid casual sexual intercourse and use a condom. If a frozen pregnancy is repeated two or more times, an in-depth examination is required.